Making Sense of Window Types And Terminology

Awning Window
A single sash window that opens out from the bottom.

Bay Window
Three or more windows, typically with a larger unit in the centre, mulled together on a 30 or 45 degree angle, projecting out from the exterior wall.

Bow Window
Four or more windows mulled together on a 10 or 15 degree angle, projecting out from the exterior wall.

Casement Window
A window with a hinged sash that swings out like a door.

Double Hung
A window made of two movable sashes that slide up and down and tilt in.

Double Slider
A window made of two movable sashes that slide horizontally.

Fixed  Sash Window
Non-venting or non-opening window.

Panoramic Picture Window
Non-venting or non-opening window with a slim frame profile.

Single Hung
A window made of one sash at the bottom that slides up and down and tilts in with one fixed sash at the top.

Single Slider
A window made of one movable sash that slides horizontally and one fixed sash.

Products that fill openings in a building envelope, including windows, doors, skylights, and curtain walls designed to permit the passage of air, light, vehicles or people.

A colourless, odourless inert gas injected between panes of glass to reduce thermal transfer

The trim around a window that adds a unifying design element regardless of the type of window

Exposed molding around the window that covers the interior and exterior edge of the frame and rough opening.

Egress Window
A window large enough and low enough for exit in case of an emergency. Building codes apply.

Double Glazing
Two panes of glass spaced apart and sealed to form a complete glazed unit with an air space.

Indicates the rate of heat transfer.The lower the number, the slower it transfers heat from a warm area to a cold area.

Indicates the resistance to heat transfer. The higher the number, the more insulative it is.

Solar Heat Gain Coefficient
The (SHGC) indicates the amount of solar gain through a window. The higher the number, the better the solar gain.

ER Rating
Calculated using a formula that balances a product’s U-value with it’s potential solar gain coefficient and it’s airtightness. The higher the ER number, the better the product’s thermal performance.

Fold-Down Handle
Casement handle that folds down on itself to create a smooth aesthetic with less interference to window treatments.

A strip of material used to create a seal.

A multi-pane effect created by placing decorative bars within the airspace between panes of glass.

Simuated Divided Lites
A multi-pane effect created by surface mounting decorative bars.

Low-E Glass
Layers deposited on a window glazing surface primarily to reduce the U-factor by suppressing the passage of radiant heat.

A horizontal or vertical structural member which combines adjacent window units.

Mullion Cover
Interior or exterior casing to cover the mullion joint.

Single Glazing
Use of single glass panes in a window.